The present invention relates to an aiming mechanism of a headlamp for an automobile.
FIGS. 9 to 11 show a conventional aiming mechanism of a headlamp for an automobile of the unit movable type. On the front side of a lamp housing 1, a lamp unit 2 incorporating a light source 2a is supported by an aiming mechanism which is comprised of a ball joint 3, i.e., a tilting fulcrum, and two aiming screws 4 and 5 respectively capable of advancing and retracting in the axial direction. The lamp housing 1 is provided with a hollow cylindrical bearing 6 extending forwardly, and a nut member 7, which is threadedly engaged with the aiming screw 4 (5) passed through the lamp housing 1 in the depthwise direction and projecting forward, is rotatably supported in this bearing 6. Further, a ball portion 4a (5a) is formed at a forward end portion of the aiming screw 4 (5), and is connected to a ball bearing portion 8a of a nut 8 fitted to the lamp unit 2. An engaging projection 4b (5b) is formed at a distal end of the ball portion 4a (5a), and the engaging projection 4b (5b) abuts against an inner wall of the nut 8 to prevent the aiming screw 4 (5) from rotating.
In addition, a bevel gear 7a is formed integrally with an outer periphery of the nut member 7, and a hollow cylindrical screwdriver guide 9 extending upward is formed integrally with the bearing 6. If a cross head screwdriver (hereafter simply referred to as the screwdriver) D is inserted in this screwdriver guide 9, the teeth of the screwdriver D is engaged with the teeth 7b of the bevel gear. Then, if the nut member 7 is rotated by turning the screwdriver D, the aiming screw 4 (5), which is prevented from rotating with respect to the lamp unit 2, is advanced or retracted in the axial direction (in the direction of the double-headed arrow in FIGS. 10 and 11), which in turn causes the ball bearing portion 4a (5a) to move back and forth. Consequently, the lamp unit 2 is tilted about the horizontal axis Lx and the vertical axis Ly, thereby making it possible to effect aiming adjustment.
With the above-described conventional technique, however, since only one screwdriver guide 9 for insertion of the screwdriver D is provided for each bearing 6, the operation for aiming can be effected only from one limited direction in which the screwdriver D can be inserted, so that the arrangement has been very inconvenient.
In addition, although the members constituting the aiming mechanism, such as the tilting fulcrum (ball joint) 3 and the aiming screws 4 and 5, can be used in common for the left and right headlamps, since the aiming mechanisms in the left and right headlamps are arranged such that the layouts as viewed from the front side of the tilting fulcrum (ball joint) 3 and the aiming screws 4 and 5 become symmetrical, it is difficult to adopt the lamp housing 1 for the left and right headlamps in common. Thus, there has been a limit in an attempt to make the component parts of the left and right headlamps common.